Due to the difficulty of extracting runoff depth (1~5 mm) and hydrodynamic parameters (velocity

depth

etc)

it is difficult to study the water flow structure

energy dissipation and sediment transport of runoff erosion on slope surface. Based on the principle of hydrodynamics and similarity theory

the flow similarity process of overland sediment flow on slope surface was simulated by enlarging the depth of runoff with non-conventional scale model. The results were as follows:(1) When the water depth of overland sediment flow was enlarged by 2.5 times and sediment content was 10~320 kg/m3

the errors of surface line (resistance)

velocity and erosion topography from the prototype and model of overland sediment flow were 0~0.1%

0.1%~5.3% and 0.9%~4.9%

respectively

all the errors of which were within the allowable ranges. The prototype and the model fitted the similarity transform relationship

such as geometry and motion. (2) When the water depth was 0.5~1.25 cm

the overland sediment flow was turbulent

the vertical distribution of velocities of the prototype and the model fitted the logarithmic distribution

which could be expressed by the same equation. (3) The non-conventional scale model could be used for the further studies of hydrodynamic parameters extraction

flow structure

energy dissipation and sediment transport of the overland sediment flow.